Research overview: the distinctive chromosomes of the ocelot lineage

The small cats of the ocelot lineage are unusual within the otherwise karyotypically conservative cat family for having a reduced chromosome number, the result of an ancestral chromosome fusion. This overview surveys this cytogenetic distinction, its use as a shared derived character supporting the monophyly of the South American ocelot lineage, and how it complements molecular phylogenetics in defining the group. It discusses the implications of chromosomal differences for hybridization and reproductive isolation among these cats, the integration of cytogenetic and sequence data, and how the ocelot lineage illustrates that even within a conserved family, lineage-specific genome rearrangements can mark major evolutionary branches.